A telecommunication receiver may receive data signals from more than one source, for example from a plurality of antennas. These sources may have different distances relative to the receiver, resulting in different delay times. That is, as the distances from the sources to the receiver are not the same, the signal delay times corresponding with those distances will also not be the same. As a result of this delay spread, the instances of a signal that arrives at the antennas at approximately the same point in time will typically not arrive at the receiver at the same moment.
In some telecommunication systems, multiple constituent signals are received by multiple antennas and forwarded to a central receiver, which processes the constituent signals to form a single, combined signal. In such systems, the different arrival times of the constituent signals at the receiver necessitate an input buffer to cancel the delay time differences. However, in many applications such an input buffer requires a large amount of memory, in particular when the number of antennas is large and/or when there is a large spread in the distances to the receiver and hence a large delay spread. Especially in the case of one-chip receivers this memory requirement increases the cost of the receiver.
United States Patent Application US2007/147525 discloses a gain control apparatus of an interference cancellation receiver. The known apparatus has an input buffer, an FFT unit and an output buffer. However, this known arrangement is designed to cancel interference and fails to address delay times.